public class TestAnimal  {
    public static void main(String[] args) {
        siyangyuan s = new siyangyuan();
        Gou G = new Gou();
        s.useAnimal(G);

        QingWa q = new QingWa();
        s.useAnimal(q);

        Yang y = new Yang();
        s.useAnimal(y);
    }
}
